JP7766827B2 - Semiconductor Devices - Google Patents

Description

This disclosure relates to a semiconductor device.

Conventionally, power supply devices have been proposed that incorporate a lifespan detection capacitor (equivalent to a diagnostic element) to detect the lifespan of a product (see, for example, Patent Document 1). In the technology described in Patent Document 1, the lifespan detection capacitor is electrically connected to the product's internal circuitry, and the product's lifespan is detected based on the capacitance of the lifespan detection capacitor.

Japanese Patent Application Laid-Open No. 2001-327162

However, in the technology described in Patent Document 1, the life detection capacitor acting as a diagnostic element is electrically connected to the product's internal circuitry, making it difficult to easily switch between including and not including the diagnostic element during manufacturing.

Therefore, the present disclosure aims to provide a semiconductor device that can easily switch between having and not having a diagnostic element installed during manufacturing.

The semiconductor device according to the present disclosure comprises an insulating substrate having a surface pattern provided on its surface and a back pattern provided on its back surface, a semiconductor element mounted on the surface pattern, a heat sink that encompasses the insulating substrate in a top view and is joined to the back pattern, a case that is fixed to the peripheral portion of the heat sink and that houses the insulating substrate and the semiconductor element, and a diagnostic element that is disposed within the case and that diagnoses deterioration of the semiconductor element , wherein the diagnostic element is an electrolytic capacitor having terminals for external connection, and the terminals for external connection are not electrically connected to the semiconductor element.

According to the present disclosure, the presence or absence of a diagnostic element does not affect the product, making it easy to switch between including and not including a diagnostic element during manufacturing.

The objects, features, aspects, and advantages of this disclosure will become more apparent from the following detailed description and accompanying drawings.

1 is a cross-sectional view of a semiconductor device according to a first embodiment; 1 is a graph showing characteristic values of the semiconductor device according to the first embodiment and a diagnostic element included therein; FIG. 10 is a cross-sectional view of a semiconductor device according to a third embodiment. FIG. 10 is a cross-sectional view of a semiconductor device according to a fourth embodiment. FIG. 10 is a cross-sectional view of a semiconductor device according to a fifth embodiment.

First Embodiment
First Embodiment A first embodiment will be described below with reference to the drawings. Fig. 1 is a cross-sectional view of a semiconductor device 100 according to the first embodiment.

As shown in Figure 1, the semiconductor device 100 is a power module and includes a heat sink 1, an insulating substrate 2, a semiconductor element 3, multiple lead electrodes 4, a case 7, sealing resin 8, a diagnostic element 9, and a lid 12.

The insulating substrate 2 is formed in a rectangular shape when viewed from above. The insulating substrate 2 comprises an insulating base material 2a, a surface pattern 2b provided on the surface of the insulating base material 2a, and a back pattern 2c provided on the back surface of the insulating base material 2a. The insulating base material 2a is made of ceramic or the like. The surface pattern 2b and back pattern 2c are made of a metal such as copper.

The heat sink 1 is made of a metal such as copper and is rectangular in top view. The heat sink 1 encompasses the insulating substrate 2 in top view and is bonded to the back surface pattern 2c with a bonding material 5. The bonding material 5 is, for example, solder.

The semiconductor element 3 is mounted on the surface of the insulating substrate 2. Specifically, the semiconductor element 3 is mounted on the surface pattern 2b via a bonding material 5. The semiconductor element 3 is electrically connected to the lead electrode 4 by a metal wire 6. Here, the number of semiconductor elements 3 is not limited to one, and there may be multiple semiconductor elements 3.

The semiconductor element 3 is, for example, an insulated gate bipolar transistor (IGBT) or a metal oxide semiconductor field effect transistor (MOSFET). The semiconductor element 3 may also include an electrically connected free wheeling diode (FWD). The semiconductor element 3 is made of silicon or a wide band gap semiconductor material. Wide band gap semiconductor materials include silicon carbide, gallium nitride-based semiconductor materials, and diamond.

The case 7 is formed into a rectangular frame shape when viewed from above. The case 7 is fixed to the peripheral edge of the heat sink 1 and houses the insulating substrate 2 and semiconductor element 3. The case 7 is made of resin and has insulating properties.

The diagnostic element 9 is located at the top inside the case 7. Specifically, the diagnostic element 9 is located above the semiconductor element 3 inside the case 7. The diagnostic element 9 is a component for diagnosing the deterioration of the semiconductor element 3, i.e., the deterioration of the semiconductor device 100. Diagnosis of the deterioration of the semiconductor device 100 will be described later.

The lid 12 is attached above the diagnostic element 9 so as to cover the opening 7a of the case 7. Like the case 7, the lid 12 is made of resin and is insulating. Two through holes 12a and multiple through holes 12b are formed in the lid 12. The two terminals 9a of the diagnostic element 9 protrude to the outside through the two through holes 12a. In other words, the two terminals 9a of the diagnostic element 9 are external connection terminals and are not electrically connected to the semiconductor element 3. Therefore, the operation of the diagnostic element 9 does not affect the operation of the semiconductor element 3, and the operation of the semiconductor element 3 does not affect the operation of the diagnostic element 9. In this way, the presence or absence of the diagnostic element 9 does not affect the finished semiconductor device 100, making it easy to switch between including and excluding the diagnostic element 9 during manufacturing.

One end of each of the multiple lead electrodes 4 is connected to the surface pattern 2b, and the other end protrudes to the outside through multiple through-holes 12b formed in the lid 12. The sealing resin 8, which may be epoxy resin, is filled inside the case 7.

Next, we will explain the deterioration diagnosis of the semiconductor device 100 using the diagnostic element 9 using Figure 2. Figure 2 is a graph showing the characteristic values of the semiconductor device 100 according to embodiment 1 and the diagnostic element 9 it includes.

The degradation of the semiconductor device 100 is related to the degradation of the semiconductor element 3, and the breakdown timing of the semiconductor device 100 can be considered to be the same as the breakdown timing of the semiconductor element 3. Therefore, in diagnosing the degradation of the semiconductor device 100, the breakdown timing of the semiconductor element 3 is used as the breakdown timing of the semiconductor device 100. As shown in Figure 2, the breakdown timing of the semiconductor device 100 is related to the characteristic value of the diagnostic element 9. The characteristic value of the diagnostic element 9 changes over time depending on the operating environment of the semiconductor device 100 or the temperature during operation. When the characteristic value of the diagnostic element 9 reaches a specific value, it is determined that the semiconductor device 100 has been destroyed. Therefore, by measuring the characteristic value of the diagnostic element 9, it is possible to diagnose the breakdown timing of the semiconductor device 100, i.e., the degradation of the semiconductor device 100.

Here, the module characteristics (characteristics of semiconductor device 100) in Figure 2 are the output voltage of semiconductor device 100, which become discontinuous after breakdown of semiconductor device 100. Furthermore, the diagnostic element characteristics in Figure 2 are the characteristics of diagnostic element 9, which continuously and monotonically decrease before and after breakdown of semiconductor device 100.

Note that while Figure 2 shows a case in which the characteristic value of the diagnostic element 9 monotonically decreases over time, the characteristic value of the diagnostic element 9 may also monotonically increase over time. Furthermore, any material can be used as the diagnostic element 9 as long as its characteristic value is related to the timing of breakdown of the semiconductor device 100.

The degradation diagnosis method for the semiconductor device 100 involves storing module characteristics and diagnostic element characteristics in a data server (not shown), and using the stored data as machine learning data to enable degradation diagnosis of the semiconductor device 100 from the diagnostic element characteristics. Here, the module characteristics are obtained from product shipping test data, degradation test data, and operational data from the product during actual operation.

As described above, the semiconductor device 100 according to embodiment 1 comprises an insulating substrate 2 having a surface pattern 2b on its surface and a back pattern 2c on its back surface, a semiconductor element 3 mounted on the surface pattern 2b, a heat sink 1 that encompasses the insulating substrate 2 in a top view and is joined to the back pattern 2c, a case 7 that is fixed to the peripheral portion of the heat sink 1 and houses the insulating substrate 2 and the semiconductor element 3, and a diagnostic element 9 that is disposed within the case 7 and is used to diagnose deterioration of the semiconductor element 3, the diagnostic element 9 having a terminal 9a that is not electrically connected to the semiconductor element 3.

Therefore, the presence or absence of the diagnostic element 9 does not affect the semiconductor device 100, which is the product, so it is easy to switch between including and not including the diagnostic element 9 during manufacturing.

<Second Embodiment>
Next, a semiconductor device 100 according to a second embodiment will be described. In the second embodiment, the same components as those described in the first embodiment will be denoted by the same reference numerals and the description thereof will be omitted.

In embodiment 2, the diagnostic element 9 is an electrolytic capacitor, and the structure of the semiconductor device 100 and the changes in the characteristic values of the electrolytic capacitor over time are the same as in embodiment 1, so the description will be given using Figures 1 and 2. Note that in embodiment 2, the diagnostic element 9 will be described as an electrolytic capacitor.

As shown in FIG. 1, the electrolytic capacitor is positioned above the semiconductor element 3 within the case 7. The two terminals 9a of the electrolytic capacitor protrude to the outside through two through holes 12a. In other words, the two terminals 9a of the electrolytic capacitor are terminals for external connection and are not electrically connected to the semiconductor element 3. Therefore, the operation of the electrolytic capacitor does not affect the operation of the semiconductor element 3, and the operation of the semiconductor element 3 does not affect the operation of the electrolytic capacitor. In this way, the presence or absence of the electrolytic capacitor does not affect the finished semiconductor device 100, making it easy to switch between including and not including the electrolytic capacitor during manufacturing.

Although not shown, the two terminals 9a of the electrolytic capacitor are connected to a sensor for measuring the capacitance of the electrolytic capacitor. As shown in Figure 2, the capacitance of the electrolytic capacitor decreases over time depending on the operating environment of the semiconductor device 100 or the temperature during operation.

Here, the module characteristics (characteristics of the semiconductor device 100) in Figure 2 are the output voltage of the semiconductor device 100, which become discontinuous after the breakdown of the semiconductor device 100. Also, the diagnostic element characteristics (characteristics of the electrolytic capacitor) in Figure 2 are the capacitance of the electrolytic capacitor, which continuously and monotonically decrease before and after the breakdown of the semiconductor device 100.

The degradation diagnosis method for the semiconductor device 100 is the same as in embodiment 1, so explanation will be omitted.

As described above, in the semiconductor device 100 of embodiment 2, the diagnostic element 9 is an electrolytic capacitor, so the presence or absence of the electrolytic capacitor does not affect the semiconductor device 100 as a product, and therefore it is easy to switch between including and not including the electrolytic capacitor during manufacturing.

<Third Embodiment>
Next, a semiconductor device 100A according to a third embodiment will be described. Fig. 3 is a cross-sectional view of the semiconductor device 100A according to the third embodiment. Note that in the third embodiment, the same components as those described in the first and second embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 3, in embodiment 3, the diagnostic element 9 is arranged on the surface pattern 2b in the periphery of the semiconductor element 3. By arranging the diagnostic element 9 in the vicinity of the semiconductor element 3, it is possible to obtain diagnostic element characteristics that reflect the temperature of the semiconductor element 3 in more detail. Note that in embodiment 3, the diagnostic element 9 may be an electrolytic capacitor.

As described above, in the semiconductor device 100A of embodiment 3, the diagnostic element 9 is arranged in the peripheral portion of the semiconductor element 3 on the surface pattern 2b, making it possible to obtain diagnostic element characteristics that reflect the temperature of the semiconductor element 3 in more detail, and improving the accuracy of deterioration diagnosis in the semiconductor device 100A can be expected.

<Fourth Embodiment>
Next, a semiconductor device 100B according to a fourth embodiment will be described. Fig. 4 is a cross-sectional view of the semiconductor device 100B according to the fourth embodiment. Note that in the fourth embodiment, the same components as those described in the first to third embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 4, in embodiment 4, the semiconductor device 100B has multiple (e.g., two) diagnostic elements 9. The two terminals 9a of each diagnostic element 9 are not electrically connected to the semiconductor element 3. Therefore, it is possible to obtain diagnostic element characteristics individually from each diagnostic element 9.

The two diagnostic elements 9 may both be positioned above the semiconductor element 3 within the case 7, or may be positioned on the periphery of the semiconductor element 3 on the surface pattern 2b. Alternatively, one of the two diagnostic elements 9 may be positioned above the semiconductor element 3 within the case 7, and the other may be positioned on the periphery of the semiconductor element 3 on the surface pattern 2b.

In Figure 4, two diagnostic elements 9 are provided, but the number of diagnostic elements 9 is not limited to two and may be three or more. Also, in embodiment 4, the diagnostic element 9 may be an electrolytic capacitor.

As described above, the semiconductor device 100B according to the fourth embodiment includes multiple diagnostic elements 9, and therefore data that takes into account the characteristics of multiple diagnostic elements can be used as machine learning data. This is expected to improve the accuracy of degradation diagnosis in the semiconductor device 100B.

<Fifth Embodiment>
Next, a semiconductor device 100C according to a fifth embodiment will be described. Fig. 5 is a cross-sectional view of the semiconductor device 100C according to the fifth embodiment. Note that in the fifth embodiment, the same components as those described in the first to fourth embodiments are denoted by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 5, in embodiment 5, the semiconductor device 100C includes a strain gauge 11 and a detection sample 10 to which the strain gauge 11 is attached, instead of the diagnostic element 9. The gauge lead 11a of the strain gauge 11 is an external connection terminal, and the gauge lead 11a protrudes to the outside through the through hole 12a. In other words, the gauge lead 11a of the strain gauge 11 is not electrically connected to the semiconductor element 3. Therefore, the operation of the strain gauge 11 does not affect the operation of the semiconductor element 3, and the operation of the semiconductor element 3 does not affect the operation of the strain gauge 11. In this way, the presence or absence of the strain gauge 11 does not affect the finished semiconductor device 100C, making it possible to easily switch between having and not having the strain gauge 11 installed during manufacturing.

The detection sample 10 is bonded to the surface pattern 2b with a bonding material 5. In order to obtain diagnostic element characteristics that reflect the temperature of the semiconductor element 3 in more detail, it is desirable that the detection sample 10 be bonded to the periphery of the surface pattern 2b.

In order to clearly understand the thermal history, it is desirable that the detection sample 10 be made of a material with a linear expansion coefficient greater than that of the insulating substrate 2. Furthermore, since the detection sample 10 must function even when the semiconductor device 100C is destroyed, in reliability tests the bond between the detection sample 10 and the insulating substrate 2 must be more durable than the bond between the semiconductor element 3 and the metal wire 6 and the bond between the insulating substrate 2 and the heat sink 1. The durability of the bond between the detection sample 10 and the insulating substrate 2 can be adjusted by changing the shape and bonding area of the detection sample 10.

The detection sample 10 expands and contracts depending on the operating environment of the semiconductor device 100C or the temperature during operation. Strain in the detection sample 10 accumulates over time, and the accumulated strain in the detection sample 10 is measured by the strain gauge 11. The strain in the detection sample 10 measured by the strain gauge 11 is used as a diagnostic element characteristic, and degradation diagnosis of the semiconductor device 100C is performed using a method similar to that in embodiment 1. Here, the strain gauge 11 and the detection sample 10 may be provided in multiple locations.

In addition, the strain gauge 11 may be attached directly to the surface pattern 2b without bonding the detection sample 10 onto the surface pattern 2b. In this case, the strain of the surface pattern 2b measured by the strain gauge 11 is used as the diagnostic element characteristic. In addition, the strain gauge 11 may be installed in multiple locations.

In addition, instead of the gauge lead 11a being an external connection terminal, a separate external connection terminal may be provided and the gauge lead 11a may be connected to the external connection terminal, which is a separate component.

As described above, in the semiconductor device 100C of embodiment 5, the diagnostic element 9 is a strain gauge 11, and the external connection terminal is connected to the gauge lead 11a of the strain gauge 11.

Therefore, the presence or absence of the strain gauge 11 does not affect the finished semiconductor device 100C, so it is easy to switch between installing and not installing the strain gauge 11 during manufacturing.

The diagnostic element 9 also includes a detection sample 10 to which a strain gauge 11 is attached, the detection sample 10 being arranged on the surface pattern 2b, and the external connection terminal being a gauge lead 11a.

Therefore, by using the distortion of the detection sample 10 as the diagnostic element characteristic, it is expected that the accuracy of deterioration diagnosis in the semiconductor device 100C will be improved compared to when the distortion of the surface pattern 2b is used as the diagnostic element characteristic.

Although this disclosure has been described in detail, the above description is illustrative in all respects and is not limiting. It is understood that countless variations not illustrated can be envisioned.

In addition, it is possible to freely combine each embodiment, and to modify or omit each embodiment as appropriate.

1 heat sink, 2 insulating substrate, 2b surface pattern, 2c back surface pattern, 3 semiconductor element, 7 case, 9 diagnostic element, 9a terminal, 10 detection sample, 11 strain gauge, 11a gauge lead, 100, 100A, 100B, 100C semiconductor device.

Claims (5)

an insulating substrate having a surface pattern provided on a surface thereof and a back surface pattern provided on a back surface thereof;
a semiconductor element mounted on the surface pattern;
a heat sink that includes the insulating substrate when viewed from above and is joined to the rear surface pattern;
a case fixed to a peripheral portion of the heat sink and accommodating the insulating substrate and the semiconductor element;
a diagnostic element disposed in the case for diagnosing deterioration of the semiconductor element;
the diagnostic element is an electrolytic capacitor having an external connection terminal,
The semiconductor device, wherein the external connection terminal is not electrically connected to the semiconductor element. an insulating substrate having a surface pattern provided on a surface thereof and a back surface pattern provided on a back surface thereof;
a semiconductor element mounted on the surface pattern;
a heat sink that includes the insulating substrate when viewed from above and is joined to the rear surface pattern;
a case fixed to a peripheral portion of the heat sink and accommodating the insulating substrate and the semiconductor element;
a diagnostic element disposed in the case for diagnosing deterioration of the semiconductor element;
the diagnostic element is a strain gauge having an external connection terminal,
The semiconductor device, wherein the external connection terminal is connected to a gauge lead of the strain gauge and is not electrically connected to the semiconductor element. 3. The semiconductor device according to claim 1, wherein the diagnostic element is disposed on the surface pattern in a peripheral portion of the semiconductor element. The semiconductor device described in claim 1 or claim 2, comprising a plurality of the diagnostic elements. the diagnostic element includes a detection sample to which the strain gauge is attached;
the detection sample is placed on the surface pattern;
3. The semiconductor device according to claim 2 , wherein said external connection terminal is said gauge lead.